/* Copyright (c) 2011 Glenn Ganz
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */

#import "CTTemplateParser.h"
#import "CTTemplateTextBlock.h"
#import "CTTemplate.h"
#import "CTStatementFactory.h"

#import <Foundation/Foundation.h>

NSString * const BeginExpression=@"{%";
NSString * const EndExpression=@"%}";
NSString * const BeginVariable=@"{{";
NSString * const EndVariable=@"}}";
 
@implementation CTTemplateParser

- (CTTemplate *)parseTemplateWithString:(NSString *)templateString
{
	CTTemplate	*template = [[[CTTemplate alloc] init] autorelease];
	NSScanner	*scanner = [NSScanner scannerWithString:templateString];
	NSString	*currentString = nil;

	[scanner setCharactersToBeSkipped:nil];
	while ([scanner isAtEnd] == NO) {
		if ([scanner scanUpToString:@"{" intoString:&currentString] == YES) {
			if ([currentString length] > 0) {
				CTTemplateTextBlock	*textBlock = [[[CTTemplateTextBlock alloc] initWithString:currentString] autorelease];
				[template addElement:textBlock];
				currentString = nil;
			}		
			if ([scanner scanString:@"{" intoString:NULL] == YES) {
				if ([scanner scanString:@"%" intoString:NULL] == YES) {
					//expression found
					NSString	*expressionString = nil;
					if ([scanner scanUpToString:@"%}" intoString:&expressionString] == NO) {
						[NSException raise:@"ExpressionNotTerminated" format:@"Expression not terminated on position [%d]", [scanner scanLocation]];
					};
					[scanner scanString:@"%}" intoString:NULL];
					[template addElement:[[CTStatementFactory defaultFactory] statementWithString:expressionString]];
				}
				else if ([scanner scanString:@"{" intoString:NULL] == YES) {
					//variable found
					NSString	*variableString = nil;
					if ([scanner scanUpToString:@"}}" intoString:&variableString] == NO) {
						[NSException raise:@"VariableNotTerminated" format:@"Variable not terminated on position [%d]", [scanner scanLocation]];
					};
					[scanner scanString:@"}}" intoString:NULL];
					//TODO
				}
				else {
					if ([currentString length] > 0) {
						CTTemplateTextBlock	*textBlock = [[[CTTemplateTextBlock alloc] initWithString:currentString] autorelease];
						[template addElement:textBlock];
						currentString = nil;
					}
				}
			}
			else {
				if ([currentString length] > 0) {
					CTTemplateTextBlock	*textBlock = [[[CTTemplateTextBlock alloc] initWithString:currentString] autorelease];
					[template addElement:textBlock];
					currentString = nil;
				}
			}
		}
		else {			
			if ([currentString length] > 0) {
				CTTemplateTextBlock	*textBlock = [[[CTTemplateTextBlock alloc] initWithString:currentString] autorelease];
				[template addElement:textBlock];
				currentString = nil;
			}
		}
	}
	return template;
}

@end
